Related Study On The Late Radiation-induced Injury Of Nasopharyngeal Carcinoma After Intensity Modulated Radiotherapy

Background:Nasopharygeal carcinoma（NPC）is one of the most common malignant tumors in China.The incidence of the disease is high in Guangdong,Guangxi and Fujian in China.The incidence of the disease in the north China is lower than that in the south of China.The incidence of male and female is about 2 to 3:1.Most of the pathological types of nasopharyngeal carcinoma are squamous cell carcinoma,and most of them are medium to low differentiated squamous cell carcinoma。Their pathological features,special anatomical locations,and tumor invasion properties,which make radiotherapy a preferred treatment for nasopharyngeal carcinoma.In recent decades,the continuous progress of radiotherapy technology,the rising of Intensity-modulated radiotherapy（IMRT）with higher dose of tumor irradiation and less normal tissue irradiation has made the survival of nasopharyngeal cancer patients significantly improved.Therefore,the quality of life of nasopharyngeal cancer patients after radiotherapy is paid much attention.At present,there are few conclusions on the causes and prognosis of late radiation-induced injury after radiotherapy,and the conclusion is not uniform.This study reviewed the data of 88 cases of nasopharyngeal carcinoma with intensity modulated radiation therapy,and regularly followed-up of the occurrence of late radiation-induced injury,in order to explore the causes of late injury after nasopharyngeal carcinoma（NPC）patients treated with IMRT.Object:Through reviewing the data of the patients who receive the IMRT and the treatment planning,we analyzed the prognosis of NPC patients,the degree of late radiation-induced injury and the progniosis-related risk factors.Method:We retrospectively analyzed the data of 88 cases of nasopharyngeal carcinoma undergoing radical radiotherapy from 2014.01.01 to 2016.12.31 in the Second Affiliated Hospital of Dalian Medical University,and followed up the late radiation-induced injury.Using SPSS19.0 software,counting data and the single factor analysis by Chi square test.The statistical analysis of survival was calculated by Kaplan-Meier method,log-rank test.P<0.05 indicated that the result had statistical difference.Results:1.Concurrent cisplatin chemotherapy（P=0.204）,induction and/or adjuvant chemotherapy（P=0.327）with radiotherapy are helpful to disease free survival,but the results of statistical analysis is not significant.2.In patients with nasopharyngeal carcinoma after radiotherapy,2 cases of salivary gland injury have a significant differences in dry mouth symptoms.In 6-12months the incidence of 2 grade weight in dry mouth have a significantly decreased while the incidence of 1 degrees of dry mouth increased significantly.In 18-24 months the recovery of dry mouth gradually tended to be stable,and gradually increased to 1 levels.3.Results of single factor analysis showed:Sex,T stage and V₃₀ of parotid gland were related factors to the xerostomia induced by radiotherapy.Age is the related factor of dysphagia induced by radiotherapy.The maximum dose of optic nerve is related to dizziness and headache induced by radiotherapy.The hearing impairment and memory decline after radiotherapy are light in most of nasopharyngeal carcinoma patients.Age is a risk factor for memory loss induced radiotherapy.Conclusion:1.Concurrentchemotherapy with cisplatin,induction and/or adjuvant chemotherapy with radiotherapy are helpful to the disease-free survival,but the result of statistical analysis is not significant and is considered related to the fewer number of samples.2.Patients with nasopharyngeal carcinoma will experience different degrees of salivary gland injury after intensity-modulated radiotherapy.There is a great difference in dry mouth symptoms in the 2 grade injury patients.During the 2 years after radiotherapy,the mouth dry condition gradually improved,and 2 years later,the degree of dry mouth was gradually dominated by mild dry mouth.3.The related factors of late injury in nasopharyngeal carcinoma after IMRT are varied.Analysis of its injuries in related symptoms,The sex,T staging and V₃₀of parotid gland were associated with the occurrence of dry mouth induced by radiotherapy;age was associated with dysphagia induced by radiotherapy;the maximum dose of the optic nerve was associated with the onset of dizziness and headache induced by radiotherapy,and hearing loss and memory decline were mostly mild.Age may be related to memory loss induced by radiotherapy.